Top Voted Answer

The red howler monkey is only found on Isla de Providence at the very bottom of the map. You will be marooned there automatically during sequence 9 but you won't have yer pistol or blow gun at the time so you have to go back later to kill one. Black jags can also be found there as well

Answers

The island where you find the red monkey isn't accessible tell late in the game, I believe its the one with the guardians on it. As for the white jaguar there is an assassin quest you do on an island that you have to out hunt the assassin chick who gives you the quest, you'll end up having to kill one.

The Black Jagur is usually pretty easy to find. Literally using the viewpoints to uncover each hunting zone is very nice. The white Jaguar is in the Cayman Sound. I don't remember the other's exact locations sorry.

Red howler Monkey - Isla Providencia; Hard to miss, usually one or two in the forest

Black Jaguar - Isla Providencia and Misterosia; A couple of them, usually in the open on Misterosia, near the jungles/forest, and deep in forest on Isla Providencia

White Jaguar - Cayman Sound and Templar Hunt, Opia Apito; Actually Rare on Cayman Sound, but is a mission requirement on the templar hunt, which makes it a better, easier place to kill. The skin is available right after the mission, so DON'T MISS IT.

the white jaguar is in great inagua in the jungle and the red HOWLER monkey is in an island that you have to find during a certain memory so it would be easier to get the monkey skin by just buying it. I know it costs a lot but you can earn it back fast by doing some quick (I like to call attacking ships this) plunderin' and pillagin'

White Jaguar - Great Inagua deep in jungle and First Opia Templar huntRed Howler monkey - Isla Providenca after you finish sequence 9. Unable to do in the mission Marooned since you have no access to ranged weapons in the entire mission.

The White Jaguar, I found them by accident, on Great Inagua in the jungle area trying to get back to the south shore. I looked at my map & saw a red paw coming at me, to my surprise it was the White Jaguar. Scared the hell out of me. :-O

1 place that wasn't mentioned for finding the black jaguar is Pinos Isle and 1 place that wasn't mentioned for the white jaguar is Cape Bonavista (just west of Havana, the location in Sequence 1, Memory 1).